A projection system typically includes a light source, one or more image forming components, or imagers, projection optics, and a screen. Often, imagers used in projection systems are typically polarization-rotating, image-forming devices, such as liquid crystal display imagers, which operate by rotating the polarization of the light to produce an image corresponding to digital video signals. Imagers used in projection systems typically rely on polarizers to separate light into a pair of orthogonal polarization states (e.g., s-polarization and p-polarization). Therefore, projection systems also will generally include a polarizing beam splitter to serve this purpose.
Recent technical advances have enabled the production of ultra-compact projection engines and systems that have relatively high light output (e.g. greater than 40 ANSI lumens). With these high levels of light output, and correlated light input levels from the light source, serious issues with the lifetime of the polarizing beam splitter, or beam splitters, within the projection system have arisen. Most notably, higher light intensity incident upon conventional polarizing beam splitters using polymeric reflective polarizers has led to degradation of the polymeric reflective polarizers at short lifetimes, and thus effective failure of the projection systems. It would be highly desirable to provide a projection subsystem that was capable of exposure to high intensity and doses of incident light while maintaining necessary performance over a longer lifetime.